Korean (한국어/조선말, see below) is the official language of South Korea and North Korea. It is also one of the two official languages in the Yanbian Korean Autonomous Prefecture in People's Republic of China. Approximately 78 million people speak Korean worldwide. For over a millennium, Korean was written with adapted Chinese characters called hanja, complemented by phonetic systems like hyangchal, gugyeol, and idu. In the 15th century, a national writing system called hangul was commissioned by Sejong the Great, but it only came into widespread use in the 20th century, because of the yangban aristocracy's preference for hanja.

The genealogical classification of the Korean language is debated by a number of historical linguists. Most classify it as a language isolate while a few consider it to be in the controversial Altaic language family. The Korean language is agglutinative in its morphology and SOV in its syntax.

The Korean names for the language are based on the names for Korea used in North and South Korea.